Synapsin I is structurally similar to ATP-utilizing enzymes.
Esser, L., Wang, C.R., Hosaka, M., Smagula, C.S., Sudhof, T.C., Deisenhofer, J.(1998) EMBO J 17: 977-984
- PubMed: 9463376 
- DOI: https://doi.org/10.1093/emboj/17.4.977
- Primary Citation of Related Structures:  
1AUV, 1AUX - PubMed Abstract: 
Synapsins are abundant synaptic vesicle proteins with an essential regulatory function in the nerve terminal. We determined the crystal structure of a fragment (synC) consisting of residues 110-420 of bovine synapsin I; synC coincides with the large middle domain (C-domain), the most conserved domain of synapsins. SynC molecules are folded into compact domains and form closely associated dimers. SynC monomers are strikingly similar in structure to a family of ATP-utilizing enzymes, which includes glutathione synthetase and D-alanine:D-alanine ligase. SynC binds ATP in a Ca2+-dependent manner. The crystal structure of synC in complex with ATPgammaS and Ca2+ explains the preference of synC for Ca2+ over Mg2+. Our results suggest that synapsins may also be ATP-utilizing enzymes.
Organizational Affiliation: 
Howard Hughes Medical Institute, Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235-9050, USA.